Micro-Reactor System Assembly

ABSTRACT

A micro-reactor system assembly comprises a stack of at least n process modules ( 1 - 6 ), wherein n is an integer equal to or greater than 1, made from a rigid first material and comprising at least one reactive fluid passage ( 1 A,  1 B,  2 A,  3 A,  6 A) for accommodating and guiding a reactive fluid, and at least n+1 heat exchange modules ( 7, 8 ) made from a ductile second material other than said first material and comprising at least one heat exchange fluid passage ( 7 A,  8 A) for accommodating and guiding a heat exchange fluid, wherein each process module ( 1 - 6 ) is sandwiched between two adjacent heat exchange modules ( 7, 8 ).

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation application of U.S. application Ser.No. 14/330,278, filed Jul. 14, 2014, now U.S. Pat. No. 9,375,698, whichis a continuation application of U.S. application Ser. No. 13/900,013,filed May 22, 2013, which is continuation application of U.S.application Ser. No. 13/434,210, filed Mar. 29, 2012, now U.S. Pat. No.8,512,653, which is a continuation application of U.S. application Ser.No. 13/037,643, filed Mar. 1, 2011, now U.S. Pat. No. 8,287,834, issuedon Oct. 16, 2012, which is a continuation application of U.S.application Ser. No. 12/293,188, filed Sep. 16, 2008, now U.S. Pat. No.7,919,056, issued on Apr. 5, 2011, the specifications of which areincorporated herein by reference in their entireties for all purposes.

BACKGROUND OF THE INVENTION

The present invention refers to a micro-reactor system assemblycomprising at least n process modules and at least n+1 heat exchangemodules wherein each process module is sandwiched by two adjacent heatexchange modules.

Micro-reactors are reaction devices provided for reacting of one or morereactants (typically including mixing of two or more reactants) and tosome extent for controlling the reaction of said reactants via heatingor cooling or thermal buffering said reactants before, during and/orafter mixing. Such micro-reactors for performing chemical reactionswithin small areas are known for example from EP-A-0688242,EP-A-1031375, WO-A-2004/045761 and US-A-2004/0109798.

Chemical reactions to be performed in micro-reactors can basically bedistinguished between so-called type A reactions and type B reactions.

Type A as for example organic metal reactions are very fast chemicalreactions and take place directly at mixing reactants within the mixingchamber, typically in the range of 1 sec. They may be called reactionscontrolled by the mixing process. In order to let all reactants reactcompletely and to avoid by-products, such type A reactions require fastand effective mixing of the process fluids as well as effective thermalcontrol. Such type A reactions generally require none or shortafter-reaction time and thus can be performed well in micro-reactorswith small residence volume or after-reaction volume. The residence timefor such reactions typically is in the range less than 20 sec.

Type B reactions as for example Wittig reactions or acetoacylation of anaromatic amine with diktene, on the contrary, are fast to slow reactionswith typical reaction times in the range of 1 sec. to 10 min. They runconcentration or kinetically controlled. In order to let the reactantsreact completely and to avoid by-products, such type B reactions do notrequire a very fast mixing of the reactants but rather controllablereaction conditions during the complete reaction time. Thus residencevolume and after-reaction volume must be dimensioned such that theprocess fluid remains within the micro-reactor for a long time underconditions which can be controlled easily and precisely. However, untilnow realisation of such longer residence times is difficult withconventional micro-reactors due to the small sizes and the expensivemicro-structuring. Thus conventional micro-reactors mostly are used fortype A reactions.

SUMMARY OF THE INVENTION

It is therefore an object of the present invention to provide animproved micro-reactor system assembly suitable to assure desiredresidence times during which temperature control is possible.

This object is solved by a micro-reactor system assembly according toclaim 1, comprising a stack of:

at least n process modules (1-6), wherein n is an integer equal to orgreater than 1, each process module (1-6) being made from a rigid firstmaterial and comprising at least one reactive fluid passage (1A, 1B, 2A,3A, 6A) which penetrates the interior of said process module (1-6)between at least one reactive fluid inlet port (1C, 1D, 2C, 2D, 3C, 6C)and at least one reactive fluid outlet port (1E, 1F, 2E, 3D, 6D), foraccommodating and guiding a reactive fluid, wherein in case of at leasttwo process modules (1-6) said at least two process modules (1-6) arefunctionally connected in series; and

at least n+1 heat exchange modules (7, 8) being made from a deformableor ductile second material other than said first material and comprisingat least one heat exchange fluid passage (7A, 8A) which penetrates theinterior of said heat exchange module (7, 8) between at least one heatexchange fluid inlet port (7B, 8B) and at least one heat exchange fluidoutlet port (7C, 8C), for accommodating and guiding a heat exchangefluid, wherein said at least n+1 heat exchange modules (7, 8) arefunctionally connected in series,

wherein each process module (1-6) is sandwiched between two adjacentheat exchange modules (7, 8).

The at least n process modules and the at least n+1 heat exchangemodules form each an independent module which defines at least one fluidpassage, i.e. reactive fluid passage or heat exchange fluid passage,extending completely within the interior of the module between the atleast one inlet port and the at least one outlet port.

By providing process modules and heat exchange modules made fromdifferent materials, it is possible to select the following first andsecond materials for the process modules and heat exchange modules,respectively:

For the process modules, a first material can be selected which isoptimal for the reactions of the reactants, in particular resistant tocorrosion and/or pressure and preferably selected from the groupincluding stainless steel, hastelloy, tungsten, tantalum, titanium,ceramics, silicon, graphite and/or a suitable combination of one or moreof said first materials.

For the heat exchange modules, a ductile second material can be selectedwhich is optimal for heat transfer and/or sealing, in particular heatconducting, and preferably is selected from the group from the groupincluding aluminum, aluminum alloys, copper, copper alloys, silver andsilver alloys and/or a suitable combination of one or more of saidsecond materials.

Thus by providing a micro-reactor system assembly with separate processand heat exchange modules, it becomes possible to optimise each of saidmodules for its specific duty, i.e. running the chemical reaction orcontrolling the temperature of the process.

Advantageously, providing separate modules for the chemical reactionprocess and the temperature control, respectively allows to standardisethe components of the micro-reactor system assembly. Thus, it becomespossible to provide different micro-reactor system assemblies fordifferent reactions with different residence times, different fluidvolumes, different amounts of heat to be transferred and the like. Forexample, providing heat exchange modules with larger passages foraccommodating heat exchange fluid allows to supply or remove largeramounts of heat to the same process module.

While the first material is a more rigid one, the second material is amore ductile one. Preferably the ductile second material for the heatexchange modules reversibly, i.e. elastically, or remainingly, i.e.plastically, deforms under pressure. Pressing heat exchange modules ontoan adjacent process module made from the more rigid first material likestainless steel or the like then slightly deforms the contacting surfaceof the heat exchange module such that no additional sealing betweenprocess module and heat exchange module is required.

In contrast to conventional micro-reactors where wall thickness betweenprocess fluids and heat exchange fluids has been reduced as far aspossible in order to provide good heat transfer, according to thepresent invention independent process modules and heat exchange modulesare provided. Although this increases the distance between the reactivefluids and the heat exchange fluid(s)—which has been noticed asdisadvantageously heretofore—due to optimising the separate modules withrespect to their specific duty surprisingly better process andtemperature control can be reached.

Each process module is sandwiched between two heat exchange modules andeach heat exchange module, which is not placed at an end of themicro-reactor, is sandwiched between two process modules. The heatexchange modules at the ends of the micro-reactor system assembly may beplaced between a first and second frame means, respectively, and aprocess module.

According to a preferred embodiment of the micro-reactor systemassembly, said at least n process modules comprise:

a mixing module the at least one reactive fluid passage of whichcomprising a mixing portion for receiving and mixing at least tworeactive fluids; and optionally at least one thermal adjusting moduledisposed upstream of said mixing module for adjusting a temperature ofsaid reactive fluids prior to entering said mixing module; and

at least one retention modules disposed downstream of the mixing modulefor accommodating the reactive fluid mixture.

Using more than one mixing module allows to sequentially introduce morereactive fluids for sequential reaction steps. In said mixing module thereactive fluids are mixed in a mixing portion which forms part of the atleast one reactive fluid passage and, after leaving said mixing portion,are accommodated in a first retention volume also forming part of the atleast one reactive fluid passage. Said mixing portion may have a mixingstructure like plug flow mixing or back mixing, while said firstretention volume may comprise one or more substantially straightpassages connected by elbows. Preferably the first retention volume isprovided such that a laminar flow yields.

The temperature of the reactive fluids in the mixing modules can becontrolled by the two heat exchange modules adjacent to said mixingmodule. Thereto a warm or cold heat exchange fluid is supplied to the atleast one heat exchange fluid passage within each of the two heatexchange modules, which supplies or removes heat from the process moduleby heat transfer.

As indicated above before mixing of two or more reactive fluids, saidreactive fluids may be heated or cooled. Thereto one or more thermaladjusting modules may be provided upstream of said mixing module. Saidthermal adjusting module comprises at least one reactive fluid passagefor each reactive fluid to be heated or cooled. While flowing throughsaid reactive fluid passage(s) each reactive fluid is heated or cooledby the two heat exchange modules adjacent to said thermal adjustingmodule as it has been described before for the mixing module. Byproviding different passage volumes it becomes possible to heat or coolthe different reactants differently.

After having left the mixing module the mixed reactive fluids may beaccommodated in one or more retention modules. Thereto the reactivefluid mixture leaving the mixing module enters at least one reactivefluid passage within the retention module, flows through said at leastone reactive fluid passage and leaves the retention module afterwards.During flowing through said at least one reactive fluid passage, saidreactive fluid mixture can be heated, cooled or thermally buffered bythe two heat exchange modules adjacent to each retention module in thesame way as described for the mixing and thermal changing module before.By providing different retention modules with differently formedreactive fluid passages it becomes possible to obtain differentretention conditions. It also is possible to provide two or moreretention modules communicating with one another, each retention modulebeing sandwiched between heat exchange modules, so that a largeretention volume and thereby (depending on velocity of flow) retentiontime (residence time) can be obtained while the conditions, inparticular the temperature of the reactive fluid mixture duringresidence time can be controlled easily and precisely.

Preferably the process module's reactive fluid passage for accommodatingand guiding a reactive fluid comprises a flat channel. Ideally, the flowpath of a micro-reactor is a narrow pipe whose diameter usually is lessthan 1 mm. If a laminar non-turbulent flow is required, however, theflow rate is restricted by said small section. To increase the flowrate, a plurality of such narrow pipes may be provided. But thereto thestoichiometry in all pipes must be controllable and the residence timemust be held equal for all pipes, which cannot be secured sufficientlyin real systems.

The flat channel suggested as a preferred embodiment, corresponds to acombination of parallel pipes. Thus the flow rate can be increasedsignificantly while a laminar non-turbulent flow is maintained.

It has turned out that a ratio width:height in the range of 1:4 to 1:50is suitable to yield good results. Preferably said width/height ratio isset in the range of 1:4 to 1:30. Even more preferably said width/heightratio is set in the range of 1:5 to 1:25. In exemplary embodiments awidth of 2.0 mm, a height of 10 mm and a length of 1844 mm was selectedfor the flat channel which yields a width/height ratio of 1:5. In otherembodiments the width already tested was chosen as 1.4 mm, 0.9 mm and0.5 mm respectively, yielding a width/height ratio of 1:7.14, 1:11.11and 1:20 respectively.

Due to the small width of the channel a mostly laminar flow of theprocess fluids as in single pipes could be maintained while at the sametime the flow rate (volume of process fluid per time) has beenincreased. Also only the stoichiometry of one single volume must becontrolled in the preferred embodiment.

With a flow rate of 100 ml/min residence times of 5.7, 10.2, 15.9 and22.6 sec respectively have been measured for the channels identifiedbefore, i.e. with widths of 2.0 mm, 1.4 mm, 0.9 mm and 0.5 mmrespectively. As can be seen from these measurements the residence timefor a specific micro reaction can be chosen nearly arbitrarily bycombining different modules with different residence times. Inparticular residence times up to 30 min, or preferably up to 20 min andmost preferably up to 10 min can be obtained.

In a preferred embodiment the micro-reactor system assembly comprises atleast two process modules connected in series, each being sandwiched bytwo adjacent heat exchange modules. For example, one or more mixingmodules may be combined with at least one preceding thermal adjustingmodule for bringing the reactive fluids to an optimal temperature beforemixing, and/or at least one retention module for providing requiredresidence times for the reactive fluid mixture(s). During mixing andretention the temperature of the reactive fluid mixture(s) can becontrolled by the heat exchange modules being disposed adjacent to eachmixing and retention module. An additional mixing module, optionallyaccompanierd with a preceding thermal adjusting module may be integratedbetween two retention modules to allow the implementation of asubsequent reaction by feeding further reactive fluids.

The reactive fluid passages of two subsequent process modules may beexternally connected. Thereto external detachable or fixed couplingssuch as pipes, fittings, etc. may be used. In particular tube pipes maybe soldered or welded to the modules or Swagelok quick fitting couplingsmay be used. While detachable external couplings allow easy re-use ofthe single modules and thereby increases flexibility, fixed tube pipesadvantageously avoid dead volume and can additionally increase stabilityof the complete micro-reactor system assembly.

Preferably the at least one heat exchange fluid passage within a heatexchange module comprises at least one heat exchange fluid inlet portcommunicating with a first heat exchange fluid reservoir or at least oneheat exchange fluid connection passage provided in an adjacent processmodule and at least one heat exchange fluid outlet port communicatingwith a second heat exchange fluid reservoir or a heat exchange fluidconnection passage provided in an adjacent process module. Thus two heatexchange modules sandwiching one process module can communicate via theat least one heat exchange fluid connection passage provided in theprocess module with one another. Advantageously no additional heatexchange fluid connections between said two heat exchange modules arenecessary.

If said heat exchange modules are made from a ductile material and arepressed against the process module, no additional sealing is required atthe interfaces of the at least one heat exchange fluid connectionpassages through the process module, connecting two neighbouring heatexchange modules due to slight plastic or elastic deformation of thecontacting surfaces of the heat exchange modules. In another preferredembodiment, however, additional sealings may be provided at theinterfaces of heat exchange fluid inlet ports and/or heat exchange fluidoutlet ports, additionally sealing heat exchange fluid connectioninterfaces between two subsequent heat exchange modules via the at leastone heat exchange fluid connection passage through the sandwichedprocess module. Such sealing preferably may be an annular sealing. Inparticular it may be a hard sealing made from Teflon or the like. Due tothe ductile material of the heat exchange modules it is possible to usehard sealings, thus avoiding elastic sealings like rubber or siliconwhich may embrittle.

The at least one heat exchange fluid passage of a heat exchange moduleaccommodating the heat exchange fluid may be such that a (high)turbulent flow of said heat exchange fluid yields which advantageouslyincreases heat transfer from an heat exchange module to the adjacentprocess modules. Preferably a Reynold's number equal or more than 2600is realised.

In a preferred embodiment a process module is made by joining a firstplate and a second plate with one another. Within the contacting surfaceof said first and/second plate the at least one reactive fluid passagefor accommodating at least one reactive fluid can be provided bymilling, etching or the like. Preferably said at least one reactivefluid passage is a micro structure. After joining said first and secondplate with one another by soldering, sintering, welding or the like theat least one reactive fluid passage for accommodating the reactive fluidis, except for the at least one reactive fluid inlet port and the atleast one reactive fluid outlet port, completely encased within theprocess module.

A heat exchange module may be manufactured similarly by providing atleast one heat exchange fluid passage for accommodating at least oneheat exchange fluid within one or both contacting surfaces of a firstand second plate to be joined together afterwards by soldering, weldingor the like. Alternatively, an intermediate plate may be sandwichedbetween said first and second plate, said intermediate plate comprisingone or more cut-outs. After joining said first, intermediate and secondplate with one another said cut-outs and the corresponding surfaces ofsaid first and second plate define at least one heat exchange fluidpassage for accommodating at least one heat exchange fluid.

The combination of externally connected process modules and internallyconnected heat exchange modules provide the best mode for separation ofthe at least one reactive fluid circuit and the at least one heatexchange fluid circuit and avoiding of cross contamination.

In a preferred embodiment the stack of process modules and heat exchangemodules are pressed against each other by at least a first and secondframe means. Thereto said first and second frame means may be pushedtowards one another, thereby pressing the process modules and heatexchange modules in between them against each other, by one or moretension anchors or tie-rods.

In a preferred embodiment each of said frame means optionally comprisesan inner and an outer frame. In a further preferred embodiment accordingto FIG. 17 one frame means consists of one structural element and thesecond frame means consists of an outer and an inner frame, wherein thefirst frame means is directly anchored to the outer frame via tie-rodsand said outer frame pushes said inner frame against the first framemeans and the stack of modules lying inbetween.

Said tie-rods may be provided in the centre and/or the periphery of themicro-reactor system assembly. Thus said modular micro-reactor systemassembly can be assembled easily with different numbers of modules.

Advantageously, a cavity is provided within the central area of thefirst and second frame means such that at pushing said first and secondframe means towards each other a higher pressure is obtained at acircumferential portion of the modules. This advantageously increasessealing characteristics of the micro-reactor.

In a most preferred embodiment one heat exchange module serves as anadjacent module for two subsequent process modules, i.e. in themicro-reactor system assembly, there are provided heat exchange modulesand process modules alternatingly. Advantageously this stack starts andends with a heat exchange module. If two subsequent heat exchangemodules communicate with one another via a heat exchange fluidconnection passage provided in a process module sandwiched in between,identically structured heat exchange modules may be used, wherein eachsecond module is rotated around 180° (180° rotation around a verticalaxis if it is assumed that the heat exchange fluid flows from right toleft direction), so that the at least one outlet port of the first heatexchange module, the at least one heat exchange fluid connection passageprovided in the adjacent process module and the at least one heatexchange fluid inlet port of the subsequent second heat exchange modulealign with one another.

The at least one heat exchange fluid inlet port of a very first heatexchange module and the at least one heat exchange fluid outlet port ofa very last heat exchange module of the complete micro-reactor systemassembly can communicate with a first and second heat exchange fluidreservoir, respectively, such that the heat exchange fluid flows fromthe first to the second reservoir or vice versa, thereby heating,cooling or thermal buffering the process modules of the micro-reactorsystem assembly. Thereto an inlet port and an outlet port respectivelymay be provided in the first and second frame means abutting the firstand last heat exchange modules.

Additional heat exchange fluid inlet ports and heat exchange fluidoutlet ports may be provided at heat exchange modules within themicro-reactor, communicating with a third, fourth etc. heat exchangefluid reservoir. Thus for example a warm first heat exchange fluid mayflow from the first reservoir through the heat exchange modulessandwiching the thermal adjusting module into a third reservoir, thusheating up the reactant flowing through the thermal adjusting module. Asecond, cold heat exchange fluid then may flow from a fourth reservoirthrough the heat exchange modules sandwiching the retention modules intothe second reservoir, thereby cooling the process fluids duringresidence time.

As described above, in a preferred embodiment subsequent heat exchangemodules are substantially identical, wherein each second module isrotated around 180°, so that the at least one heat exchange fluid outletport of the first heat exchange module, the at least one heat exchangefluid connection passage provided in the adjacent process module and theat least one heat exchange fluid inlet port of the adjacent second heatexchange module communicate with one another. Thus the heat exchangefluid flows in a zigzag line through the micro-reactor. Depending on thenumber of process and heat exchange modules it may become necessary toprovide two heat exchange modules adjacent to one another in order tofit to the inlet and outlet ports of the complete micro-reactor. Toavoid said two adjacent heat exchange modules they may be separated byinstallation of one blind module. Alternatively, for example, the secondframe means, in which the outlet port of the micro-reactor can beprovided, may be rotated around 180° (180° rotation around a horizontalaxis assumed the thermal heat exchange fluid flows from right to leftdirection) to match the last heat exchange module's outlet port.Alternatively, for example, a second frame means with a shifted inletport may be used.

BRIEF DESCRIPTION OF THE DRAWINGS

Further objects, advantages and features may be derived from thedepending claims and the described embodiments of the present invention.Thereto:

FIG. 1 shows a spatial view of a micro-reactor system assembly havingall fittings on one side according to one embodiment of the presentinvention;

FIG. 2 shows a spatial view rotated 180° of the micro-reactor systemassembly shown in FIG. 1;

FIG. 3 shows a frontal sectional view of a thermal adjusting module ofthe micro-reactor system assembly shown in FIG. 1;

FIG. 4 shows the thermal adjusting module of FIG. 3, seen from the left;

FIG. 5 shows a frontal sectional view of a mixing module of themicro-reactor system assembly shown in FIG. 1;

FIG. 6 shows an enlarged view of an upper left corner indicated “X” inFIG. 5;

FIG. 7 shows a frontal sectional view of a retention module of themicro-reactor system assembly in FIG. 1;

FIG. 8 shows a top sectional view of the mixing module of FIG. 7 seenfrom above;

FIG. 9 shows an enlarged view of a reactive fluid inlet port of themixing module shown in FIG. 8;

FIG. 10 shows a frontal sectional view of another retention module ofthe micro-reactor in FIG. 1;

FIG. 11 shows a top sectional view of the mixing module of FIG. 10 seenfrom above;

FIG. 12 shows an enlarged view of a reactive fluid inlet port of themixing module of FIG. 10;

FIG. 13 shows a frontal sectional view of a first heat exchange module;

FIG. 14 shows a side sectional view of the heat exchange module of FIG.13;

FIG. 15 shows a frontal sectional view of a second heat exchange module;

FIG. 16 shows a side sectional view of the heat exchange module of FIG.15; and

FIG. 17 shows a longitudinal section of a micro-reactor system assemblyaccording to one embodiment of the present invention;

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The micro-reactor system assembly according to one embodiment of thepresent invention as shown in FIGS. 1, 2 comprises a first frame means10, a first heat exchange module 7, a thermal adjusting module 1 as aprocess module, a second heat exchange module 8, a mixing module 2 as afurther process module, another first heat exchange module 7, aretention module 3 as a further process module, another second heatexchange module 8, further retention modules 4, 5 and 6 respectively,each sandwiched between two heat exchange modules 7, 8 and a secondframe means 9 in this sequence. Thus, between said first and secondframe means 10, 9 alternating a first or second heat exchange module 7,8 and a process module 1-6 are provided.

As can be seen best from FIGS. 14, 16, each heat exchange module 7, 8,comprises a first plate 7M, 8M, an intermediate plate 70, 80 and asecond plate 7N, 8N respectively, joined together by soldering. Theintermediate plate comprises a cut-out in the form of parallel straightpassages, wherein two subsequent passages are connected by a half circlesuch that one continuous sinusoidal cut-out is formed. Said cut-out ofthe intermediate plate 70, 80 and the inner surfaces of the first andsecond plate 7M, 7N and 8M, 8N respectively thus define a heat exchangefluid passage 7A, 8A for accommodating a heat exchange fluid in the heatexchange module 7, 8. At one end of the cut-out a through hole is formedin the first plate 7M, 8M, and another through hole is formed at theopposite end of the cut-out in the second plate 7N, 8N to define a heatexchange fluid inlet port 7B, 8B and a heat exchange fluid outlet port7C, 8C respectively, communicating with the heat exchange fluid passage7A, 8A.

As can be seen from FIGS. 13-16, the first and second heat exchangemodules 7, 8 are substantially identical, wherein the second heatexchange module 8 is rotated around 180°. Thus, when assembled, theoutlet port 7C of a first heat exchange module 7 and the heat exchangefluid inlet port 8B of a second heat exchange module 8 align with eachother as well as the heat exchange fluid outlet port 8C of the secondheat exchange module 8 with the inlet port 7B of a next first heatexchange module 7.

As can be seen from FIGS. 3, 5, 7 and 10, each process module 1-3, 6comprises two through holes 1H-3H, 6H, one of which, when assembled,corresponds with a heat exchange fluid inlet port 7B, 8B while the otherof which corresponds with a heat exchange fluid outlet port 7C, 8C offirst and second heat exchange modules 7, 8 sandwiching said eachprocess module 1-3, 6. Thus the heat exchange fluid passage 7A, 8A foraccommodating and guiding a heat exchange fluid in a first heat exchangemodule 7 and in a second heat exchange module 8 communicate with oneanother via a heat exchange fluid connection passage formed by throughholes in a corresponding one of process modules 1-6 sandwiched betweensaid first heat exchange module 7 and second heat exchange module 8,when assembled, as can be seen from FIGS. 1, 2 and 17.

The heat exchange fluid inlet port 7B of the very first heat exchangemodule 7 communicates with a first heat exchange fluid reservoir (notshown) through a passage provided in the first frame means 10 and afirst coupling part 12A connected thereto. The heat exchange fluidoutlet port 8C of the last heat exchange module 8 communicates with asecond heat exchange fluid reservoir (not shown) via a passage providedin the second frame means 9 and a second coupling part 12B connectedthereto. Thus for example a warm heat exchange fluid can flow from thefirst reservoir through the first coupling part 12A, the first frame 10,groups of first and second heat exchange modules 7, 8 communicating viaheat exchange fluid connection passages provided in process modules 1-6sandwiched by said first and second heat exchange module 7, 8, secondframe 9 and second coupling part 12B into a second reservoir in a zigzagline, thereby subsequently heating all process modules 1-6 via heatexchange through the module plates.

A temperature adjusting module 1, which is shown in further detail inFIGS. 3, 4 is provided as a first process module. Said temperatureadjusting module 1 comprises a first reactive fluid passage 1A,communicating with a first reactive fluid inlet port 1C and a firstreactive fluid outlet port 1F, and a second reactive fluid passage 1Bcommunicating with a second reactive fluid inlet port 1D and a secondreactive fluid outlet port 1E. A first reactive fluid is supplied to thefirst reactive fluid passage 1A through the first reactive fluid inletport 1C. A second reactive fluid is supplied to the second reactivefluid passage 1B through the second reactive fluid inlet port 1D.

Said temperature adjusting module 1 comprises a first and second plate1M, 1N (FIG. 4), which are joined with one another by soldering or thelike. Into the contacting surfaces of the first and/or second plate 1M,1N the sinusoidal reactive fluid passages 1A, 1B are cut by etching,milling or the like.

While flowing through said first reactive fluid passage 1A toward saidfirst reactive fluid outlet port 1F, said first reactive fluid'stemperature is adjusted by the two heat exchange modules 7, 8sandwiching said temperature adjusting module 1. Thereto the heatexchange fluid flowing through said heat exchange modules 7, 8 suppliesor removes heat to said first reactive fluid by heat conduction throughthe plates 7N, 8M of the heat exchange modules contacting the plates 1M,1N of said temperature adjusting module.

A mixing module 2 as a second process module is shown in FIGS. 5, 6.Although not shown in detail, said mixing module 2 comprises a first andsecond plate similar to the temperature adjusting module 1 describedabove. In said mixing module a reactive fluid passage 2A is providedcomprising a mixing section 2G and a first retention section 2I.

A first reactive fluid inlet port 2C communicating with said reactivefluid passage 2A is connected with the first reactive fluid outlet port1F of the temperature adjusting module 1 by an external connection (notshown). A second reactive fluid inlet port 2D also communicating withthe reactive fluid passage 2A, is connected with the second reactivefluid outlet port 1E of the temperature adjusting module 1 similarly.Thus, the first and second reactive fluids respectively, after havingpassed through said temperature adjusting module 1, flow into the mixingsection 2G of the passage 2A within the mixing module 2, wherein saidboth reactive fluids are mixed with one another. The geometry of themixing section 2G, as shown in enlarged view in FIG. 6, can be chosenappropriately to mix the reactive fluids in an optimal way. After beingmixed, the resulting process fluid flows into the first retentionsection 2I of the reactive fluid passage 2A which basically is formed asa flat channel, thus providing an substantially laminar flow of theprocess fluids.

It shall be emphasised that the geometry of the passages of the processand heat exchange modules 1-6, 7, 8 are not limited to the ones shown inthe figures and described with respect to preferred embodiments, but maybe chosen in any appropriate design.

During mixing and residence within the mixing section 2G and firstretention section 2I, the chemical reaction can be temperaturecontrolled by the two heat exchange modules 8, 7 sandwiching said mixingmodule 2.

The process fluid, leaving the reactive fluid passage 2A through areactive fluid outlet port 2E, enters a reactive fluid inlet port 3C ofa first retention module 3 shown in FIGS. 7-9. Thereto the reactivefluid outlet port 2E and reactive fluid inlet port 3C are externallyconnected via a tube pipe or the like (not shown). The retention module3, as the other retention modules 4-6, basically comprises a first plate3M-6M joined with a second plate 3N-6N by soldering, welding or thelike. Between said two plates a passage 3A-6A is provided foraccommodating the process fluids during residence time. Thereto abasically sinusoidal flat channel is carved into the contacting surfaceof the first and/or second plate by etching, milling or the like.

While flowing through said reactive fluid passage 3A, the process fluidis temperature controlled by the two heat exchange modules 7, 8 adjacentto said retention module 3 as described for the temperature adjustingmodule 1 and mixing module 2 before.

After leaving the first retention module 3 via a reactive fluid outletport 3D, the reactive fluid enters the subsequent retention modules 4-6via a respective reactive fluid inlet port connected with the reactivefluid outlet port of a preceding retention module as described beforefor the reactive fluid inlet port 3C and the reactive fluid outlet port2E. In this manner the reactive fluid can flow through all subsequentretention modules 4-6 before leaving the micro-reactor system assemblythrough the last process module's outlet port 6D.

The residence time within each retention module 3-6 is defined by theretention volume, i.e. the section (width×height)×length of the passage3A-6A accommodating the process fluid, divided by the flow rate. Thus,by providing different widths, lengths, and/or heights of the singlepassages, different residence times can be obtained. By combiningdifferent retention modules with different passage geometries, thereforethe residence time can nearly arbitrarily be chosen.

As can be seen from comparison of FIGS. 9 and 12, showing the reactivefluid inlet ports 3C, 6C of the first and fourth retention modules 3 and6, respectively, the width of the flat channel defining the reactivefluid passages 3A, 6A respectively, can be made smaller (FIG. 9),substantially equal or larger than the width of the reactive fluid inletport's width.

As shown in FIGS. 1, 2, two tie-rods 13 push first and second framemeans 10, 9 towards each other, thereby pressing the stacked heatexchange modules 7, 8 and process modules 1-6 against one another.Placing tie-rods 13 at the circumference of the micro-reactor systemassembly and providing a cavity (see FIG. 17) within the centre of thesurfaces of the frame means 10, 9 contacting the heat exchange modules7, 8, a high pressure can be obtained at the circumference of themicro-reactor system assembly. Thus the heat exchange fluid inlet ports7B, 8B and heat exchange fluid outlet ports 7C, 8C of the heat exchangemodules 7, 8, which also are provided at the circumference of themicro-reactor system assembly, are pressed against the heat exchangefluid connection passages 1H-6H in the process modules 1-6 with highpressure. If the heat exchange modules 7, 8 are made from a ductilematerial like aluminium, copper or an alloy therefrom for example, thecircumferential edge of the inlet and outlet port will deform slightlyunder pressure, thereby providing good sealing against the surface ofthe process module 1-6 sandwiched in between. Thus the heat exchangefluid outlet port 7C, 8C and heat exchange fluid inlet port 7B, 8B oftwo subsequent heat exchange modules 7, 8 communicate fluid-tight viathe heat exchange fluid connection passage 1H-6H provided in theintermediate process module.

Additionally, there may be provided a ring sealing around the heatexchange fluid inlet ports 7B, 8B and heat exchange fluid outlet ports7C, 8C. Thereto for example a circular groove may be provided within thefirst and second plates 7M, 7N, 8M, 8N respectively, accommodating aring sealing therein (not shown). Such ring sealing may be made fromrubber, silicon or—preferably—Teflon or the like.

As can be understood from the foregoing description, a micro-reactorsystem assembly according to the present invention provides due to itsmodular structure high flexibility and allows combining different mixingchannel geometries with different retention modules, thereby providingarbitrarily chosen residence times, in particular for type B reactions.Each of said process modules 1-6 is temperature controlled by twoadjacent heat exchange modules 7, 8. Since heat transfer only isrealised by heat conduction through the plates 1M-8M, 1N-8N of the heatexchange modules 7, 8 and process modules 1-6 no sealing or the like isnecessary. Furthermore, advantageously the process modules 1-6 may beoptimised with respect to the reactants accommodated therein, forexample being resistant to corrosion and/or pressure, while at the sametime the heat exchange modules 7, 8 not coming into contact with thereactants, can be optimised with respect to heat transfer and/or sealingcharacteristics.

In the embodiment described above heat exchange modules 7, 8 and processmodules 1-6 are stacked alternating with one another and the heatexchange fluid flows from a first reservoir through first coupling part12A in a zigzag line through all heat exchange modules 7, 8 into asecond reservoir connected to second coupling part 12B. Thereby all heatexchange fluid connections of the heat exchange modules 7, 8 areinternally provided without any additional connections. Advantageously,standardised process and heat exchange modules may be used, thus makingit possible to assemble different micro-reactors with differentresidence time and the like in an easy, modular way.

In the embodiment described above, one temperature adjusting module 1,one mixing module 2 and four retention modules 3-6 have been combined inthis order. However, an arbitrary combination of such modules ispossible. For example more temperature adjusting modules may be providedto increase the passage in which the reactants are heated up or cooleddown. More mixing modules may be provided for a multi-stage reaction.Different retention modules may be provided to realise the requiredresidence time.

With a given flow rate of for example 100 ml/min, a process module'spassage length of about 1844 mm, a passage height of 10 mm and a passagewidth of 0.5-2 mm residence times of 6-22 sec per module have beenrealised in an example testing. Thus overall residence times of up to 30min can be realised.

Surprisingly it has turned out that the external connection ofsubsequent process modules 1-6 does not effect significantly thetemperature control of the micro-reactor. Since each process module 1-6,in particular each retention module 3-6, can be very efficientlytemperature controlled (heated, cooled or thermal buffered) from twosides, reactions can be run in the micro-reactor within a broadtemperature range. As in the example of the described embodiment,preferably one heat exchange module 7, 8 transfers heat from and tosubsequent process modules 1-6 (except for the very first and last heatexchange module).

The reactive fluid passages in the process modules 1-6 aremicro-structured by etching, milling or the like. Since the heatexchange modules 7, 8 are manufactured separately, they may bemanufactured without the micro-structuring, thus reducing costs.Furthermore, since said heat exchange modules 7, 8 do not come intocontact with the reactants, they do not need to be resistant tocorrosion or high process pressures, thus allowing the use of materialsoptimised for heat transfer. In particular the following materials maybe used for the heat exchange modules.

Aluminum alloy AlMgSi1 (=EN AW-6082 or EN6082):

EN AW-6082 EN AW-AlSi1MgMn AlMgSi1 DIN 3.2315

EN AW-6061 EN AW-ALMg1SiCu AlMg1SiCu DIN 3.3211

EN AW-6005A EN AW-AlSiMg(A) AlMgSi0,7 DIN 3.3210

EN AW-6012 EN AW-AlMgSiPb AlMgSiPb DIN 3.0615

EN AW-6060 EN AW-AlMgSi AlMgSi0,5 DIN 3.3206

On the contrary the process modules 1-6 may be made from the followingmaterials for example

DIN 1.4571 AlSl 316 Ti X 10 CrNiMoTi 18 10

DIN 2.4602 NiCr21Mo14W Hastelloy C-22

DIN 2.4610 NiMo16Cr16Ti Hastelloy C-4

DIN 2.4617 NiMo28 Hastelloy B-2

DIN 2.4819 NiMo16Cr15W Hastelloy C-276

DIN 2.4816 NiCr15Fe Inconel 600

DIN 2.4856 NiCr21Mo9Nb Inconel 625

DIN 2.4858 NiCr21Mo Inconel 825

What is claimed is:
 1. A micro-reactor system assembly, comprising astack of: at least n process modules, wherein n is an integer equal toor greater than 1, each process module being made from a first materialand comprising at least one reactive fluid passage extending between atleast one reactive fluid inlet port and at least one reactive fluidoutlet port for accommodating and guiding a reactive fluid, wherein, incase of at least two process modules, said at least two process modulesare connected in series; and at least n+1 heat exchange modules, each ofsaid heat exchange modules being made from a second material other thansaid first material and comprising at least one heat exchange fluidpassage extending between at least one heat exchange fluid inlet portand at least one heat exchange fluid outlet port for accommodating andguiding a heat exchange fluid, wherein said at least n+1 heat exchangemodules are connected in series, wherein each process module issandwiched between two adjacent heat exchange modules, and wherein saidsecond material is more ductile than said first material.
 2. Amicro-reactor system assembly according to claim 1, wherein said firstmaterial is resistant to corrosion and pressure and is selected from thegroup consisting of stainless steel, hastelloy, tungsten, tantalum,titanium, ceramics, graphite and/or a combination of one or more of saidfirst materials; and said second material is heat conducting and isselected from the group consisting of aluminum, aluminum alloys, copper,copper alloys, silver and silver alloys and/or a combination of one ormore of said second materials.
 3. A micro-reactor assembly according toclaim 1, wherein said second material deforms when pressed against saidat least n process modules for providing a fluid-tight seal between eachheat exchange module and each process module at a contacting surface ofeach heat exchange module adjacent each heat exchange fluid inlet portand each heat exchange fluid outlet port.
 4. A micro-reactor assemblyaccording to claim 3, wherein said second material elastically deformsunder pressure.
 5. A micro-reactor assembly according to claim 3,wherein said second material plastically deforms under pressure.
 6. Amicro-reactor assembly according to claim 1, wherein each process modulefurther comprises a heat exchange fluid connection passage in fluidcommunication with said heat exchange fluid inlet port of one of saidtwo adjacent heat exchange modules and is in further fluid communicationwith said heat exchange fluid outlet port of the other of said twoadjacent heat exchange modules for fluidly connecting said at least oneheat exchange fluid passage of said two adjacent heat exchange modulesin series.
 7. A micro-reactor assembly according to claim 6, whereineach of said heat exchange fluid inlet port and each of said heatexchange fluid outlet port of each heat exchange module is defined by acircumferential edge, said circumferential edge deforming when pressedagainst a process module for providing a fluid-tight seal between eachheat exchange module and each process module at a contacting surface ofeach heat exchange module adjacent each heat exchange fluid inlet portand each heat exchange fluid outlet port.
 8. A micro-reactor systemassembly according to claim 1, wherein said at least n process modulescomprise: a mixing module, the at least one reactive fluid passage ofwhich comprising a mixing portion for receiving and mixing at least tworeactive fluids; a thermal adjusting module disposed upstream of saidmixing module for adjusting a temperature of said at least two reactivefluids prior to entering said mixing module; and one or more retentionmodules disposed downstream of the mixing module for accommodating thereactive fluid mixture.
 9. A micro-reactor system assembly according toclaim 1, wherein said at least one reactive fluid passage is a flatpassage comprising curved and/or straight parts to enable a flow of therespective reactive fluid along a tortuous path, said flat passagehaving a width/height ratio in the range of 1:4 to 1:50.
 10. Amicro-reactor according to claim 1, wherein said at least n processmodules comprise at least two process modules which are externallyconnected in series.
 11. A micro-reactor system assembly according toclaim 1, wherein said at least n+1 heat exchange modules comprise: afirst heat exchange module, the at least one heat exchange fluid inletport of which communicates with a first heat exchange fluid reservoirand the heat exchange fluid outlet port of which communicates with asucceeding heat exchange module; a second heat exchange module, the atleast one heat exchange fluid outlet port of which communicates with asecond heat exchange fluid reservoir and the heat exchange fluid inletport of which communicates with a preceding heat exchange module; and atleast one further heat exchange module disposed between said first heatexchange module and said second heat exchange module and connected inseries with the first heat exchange module and second heat exchangemodule, wherein the series connection of two successive heat exchangemodules is implemented internally via at least one heat exchange fluidconnection passage passing through a respective one of the at least nprocess modules sandwiched by the two successive heat exchange modules.12. A micro-reactor system assembly according to claim 1, wherein saidat least n process modules and/or said at least n+1 heat exchangemodules comprise each a first plate and a second plate permanentlyjoined with one another by soldering, brazing, welding or gluing, andwherein each of said reactive fluid passages, heat exchange fluidpassages, reactive fluid inlet ports and reactive fluid outlet ports,and/or heat exchange fluid inlet ports and heat exchange fluid outletports is provided between said first plate and said second plate.
 13. Amicro-reactor system assembly according to claim 12, wherein each ofsaid reactive fluid passages, heat exchange fluid passages, reactivefluid inlet ports and reactive fluid outlet ports, and/or heat exchangefluid inlet ports and heat exchange fluid outlet ports is formed byablating an inner surface of at least one of said first plate and saidsecond plate.
 14. A micro-reactor system assembly according to claim 12,wherein a structured intermediate plate is sandwiched between said firstplate and said second plate of said at least n+1 heat exchange modulesto provide said heat exchange fluid passages.
 15. A micro-reactor systemassembly according to claim 1, further comprising a first frame meansand a second frame means, wherein said at least n process modules andsaid at least n+1 heat exchange modules are pressed against each otherby said first and second frame means.
 16. A micro-reactor assemblyaccording to claim 15, further comprising at least two tie-rods disposedat a circumference of said micro-reactor system assembly between saidfirst and second frame means for pressing said at least n processmodules and said at least n+1 heat exchange modules together.